The condylar articular cartilage is a mandibular growth site. As a result, developmental abnormalities at this location manifest as altered growth on the affected side of the condyle, mandibular ramus, mandibular body, and alveolar process. There are many causes of the various growth disturbances and abnormalities of the mandibular condyle and related structures. The authors report an interesting case of unilateral severe condylar hypoplasia secondary to chronic ear infection in childhood. Coronoid hyperplasia was also present on the ipsilateral side.

Deviations in the growth of the mandibular condyle can affect both the functional occlusion and the esthetic appearance of the face. Hypoplasia or aplasia of the mandibular condyle indicates underdevelopment or nondevelopment associated mainly with various craniofacial abnormalities. These may be either congenital or acquired.[1] Congenital condylar hypoplasia is characterized by unilateral or bilateral underdevelopment of the mandibular condyle and usually occurs as part of some systemic condition originating in the first and second branchial arches which include Treacher-Collins, Goldenhar, Proteus, Morquio, and Auriculo-condylar syndrome.[2] Acquired (secondary) condylar hypoplasia may be caused by local factors (trauma, infection of the mandibular bone or middle ear, irradiation) or by systemic factors (toxic agents, rheumatoid arthritis, mucopolysaccharidosis).[1] An interesting case of unilateral severe condylar hypoplasia secondary to chronic ear infection in childhood is presented. Coronoid hyperplasia was also present on the ipsilateral side as an incidental finding.

Case Report

A 23-year-old Indian female reported to the outpatient department with the chief complaint of facial asymmetry that had worsened over a period of 12 years. The patient was relatively alright about 12 years back.

Since then she complained of a progressive facial asymmetry which had gradually increased in severity.

The patient also felt that her lower jaw deviated to one side while opening her mouth. There was no complaint of pain or discomfort associated with the condition. During anamnesis, the patient reported a history of recurrent infections of the ear on the right side starting from the age of 10 to 16 years of age. She suffered from intermittent pain and pus discharge from the right ear during this period. She was prescribed medicines for the morbidity, the details of which were not available. In addition, her family history was negative for craniofacial abnormalities.

The patient was generally healthy. The extraoral examination revealed an obvious facial asymmetry, with the chin deviated to the right side. The right side of the face appeared fuller [Figure 1]. On palpation, the movements of the right temporomandibular joint (TMJ) were restricted and the observed mouth opening was slightly lesser than normal, i.e. 35 cm. There was a deviation of the mandible to the right on the complete opening of the mouth [Figure 1]. A deep antegonial notch was palpable on the right side. Intraorally, the cant of the occlusal plane was tilted to the left. As the clinical findings were consistent with those of TMJ ankylosis a working diagnosis of early ankylosis of the right TMJ was made.

Figure 1: Extraoral photograph showing chin deviated to the right side and deviation of the mandible to the right on opening

The panoramic radiographic exam revealed a deep antegonial notch and an astonishing finding of the complete absence of the right condylar process of the mandible. The coronoid process on the right side appeared elongated [Figure 2]. Thus, the two-dimensional image of the right TMJ suggested an appearance of right condylar agenesis and right coronoid hyperplasia. A computerized tomographic scan with three-dimensional (3D) reconstruction was advised to ascertain this.

The axial computed tomography (CT) section confirmed the findings of the panoramic radiograph revealing a severely hypoplastic condyle on the right side. There was associated hypoplasia of the right mandibular body and ramus [Figure 3]. The 3D CT findings revealed a severely hypoplastic right mandibular condyle measuring about 0.5 cm with a concomitant hypertrophy of the coronoid process was noted on the right side. The coronoid process measured about 1.8 cm. It extended 1 cm beyond the zygomatic arch [Figure 4]. The left TMJ appeared normal. Thus, a final diagnosis of severe hypoplasia of the right mandibular condyle and hyperplasia of the right coronoid process was made. The cause of the condition could be attributed to the chronic middle ear infection of the right side, as prior to the age of 11 years the patient had an absolutely normal facial appearance. She was referred to the department of oral and maxillofacial surgery for the appropriate surgical management of the deformity. The patient was treated with a sliding genioplasty of the chin to redeem her facial esthetics.

The cases of condylar hypoplasia in which infection is the primary etiology, septic, and destructive arthritis develop as a result of penetration of an infection such as suppurative otitis media into the joint capsule.[3] The affected side fails to grow downward and forward, resulting in a 3D asymmetry. The mandibular skeletal midline deviates to the affected side, a lack of vertical growth on the same side produces a cant of the occlusal plane, and mandibular retrognathia is seen as a result of the hypoplasia. The severity of the deformity depends on the degree of hypoplasia or agenesis of the tissues involved.[4]

Coronoid hyperplasia is an abnormal elongation of the coronoid process, formed of histologically normal bone without any synovial tissue around it.[5] Clinically, there is a progressive decrease in mouth opening, usually bilateral and painless. It often appears during puberty affecting predominantly males.[6] The exact etiology of coronoid hyperplasia is not yet elucidated, but several theories have been postulated, including hyperactivity of the temporal muscle that causes reactive elongation of the coronoid process, dysfunction of the TMJ caused by chronic disc displacement, inflammation, endocrine stimuli, traumatism, and genetic and family factor.[5] In one of the studies, ankylosing spondylosis has also been said to cause mandibular elongation (Bechterew disease).[7] Both these conditions can be evident on routine panoramic radiography. 3D CT images provide an accurate quantitative assessment of skeletal as well as muscular parameters.

The treatment modalities for mandibular condylar hypoplasia vary dependent on the age of the patient. In growing patients, orthopedic treatment with functional appliances is often helpful in correcting deformities or in reducing the worsening of deformities with growth.[8],[9] If the facial asymmetry develops progressively during orthopedic treatment, mandibular distraction osteogenesis or surgical reconstruction of the TMJ with a costochondral graft of the remaining ramus tissue may be considered.[10],[11] After the patient has stopped growing, skeletal deformities can be corrected only by double jaw surgery and/or genioplasty or unilateral mandibular augmentation.[12] For the treatment of coronoid process hyperplasia intraoral coronoidotomy combined with prolonged postoperative physiotherapy gives satisfactory and stable long-term results in the correction of coronoid-malar interference.[13] Since our patient did not experience any difficulty due to the slightly reduced mouth opening no intervention was done for the coronoid hyperplasia [Table 1] enlists the radiographic differential diagnoses for condylar hypoplasia and coronoid hyperplasia.[14]

Although middle ear infection is a well-described cause of condylar hypoplasia, there is no previous report of condylar hypoplasia occurring as a result of it. Most cases of hypoplasia and aplasia of mandibular condyle, reported in the literature have occurred as a part of syndromic entities, trauma, or as isolated cases of true agensis in nonsyndromic patients. Moreover, this case is unique due to the synchronous presence of ipsilateral coronoid hyperplasia. To the best of our knowledge, the present case is a first of its kind to be reported.

Conclusion

Unilateral condylar aplasia and coronoid hyperplasia are rare disorders of mandibular growth. Careful history, clinical, and radiographic examination will usually reveal the true nature of these conditions. As these conditions can cause challenges in diagnosing, they have to be carefully differentiated with other similar conditions for planning and initiating the proper treatment modality for both functional activity and for esthetic appearance.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.